Simulation And Research On Structural Stability And Unsteady Flow Field Of Bag Filter

Bag filter design mainly refers to structural safety and its high efficiency, which is decided by the mechanical properties of main steel structure and the features of flow field in the bag filter. In recent years, the collapse accidents of bag filter happened a lot, then its reason is researched by the enterprise and university, and how to ensure the safety of the steel structure and reduce the steel consumption in the meanwhile becomes the key point. One of the main reasons is Structural unstability.Because of the imperfection of stability theory and complexity of the structure stability analysis, the research on it is still not too much. Among them the effect of the nonlinear factors of the physical and geometry equations and the structural initial defects is the hot point. In the practical operation, the breakage of the bag fliter often happens, and running resistance becomes too high. They seriously reduce the efficiency of bag filter. Many researchers use the steady-state analysis method to simulate the flow field of inner bag filter. But in the real bag filter the flow field is not steady. Filtration time, cleaning and airflow distribution make the thickness of dust layer change, then the bag-permeability change. The airflow velocity and its distribution, in turn, is effcted by the bag-permeability’s change. In view of the above questions, this paper research on bag filter’s structure stability and inside transient flow field of bag-room with online cleaning model by computer simulation technology. Main jobs and conclusions have done as follows:1. Do enginvalue buckling analysis, geometric nonlinear buckling analysis and double(geometric and material) nonlinear analysis buckling analysis on the bag filter’s middle box which has stiffened plate structure, and study the influence of the geometric nonlinear and material nonlinear on the middle box stability.2. Do enginvalue buckling analysis, double nolinear buckling analysis with imperfection and the one without imperfection on the bag filter’s supporting structure--steel bracket. And study the influence of the geometric nonlinear, material nonlinear and imperfection on the stablity of steel bracket.3. By studying chinese and foreign literature deeply, it establishes a pressure drop model of bag at the nonstationary filtration stage. And with UDF function in the Fluent software, it simulates unsteady flow field in the bag room with online timing cleaning systerm. It also studies the influence of cleaning cycle, the average filtration velocity and the bag number on characteristics of inner flow field.4. To the online timing row-by-row cleaning systerm, it gives a method for calculating the cleaning cycle, which could provid some reference of how to set in the practical application.